Elton John feat. George Michael, "Don’t Let the Sun Go Down on Me" (1991)

Sixteen years after Elton John's original, solo version of "Don't Let the Sun Go Down on Me" was released, John joined Michael in concert for an arena-scale duet of the ballad. This wasn't the first time the pair sang the song together – they first joined forces at Live Aid in 1985, but their 1991 reunion led to a Number One hit in the U.S. and U.K. and a Grammy nomination. Proceeds from the song's immense sales went to charities for AIDS, education and children.